The present invention is directed to ink compositions and, more specifically, the present invention relates to semi-solid hot melt inks with for example, a melting point of from about 25.degree. C. to about 40.degree. C., or from about 30 to about 35 degrees Centigrade, and which inks are especially useful for acoustic ink printing, processes and apparatuses, reference, for example, U.S. Pat. No. 5,121,141, U.S. Pat. No. 5,111,220, U.S. Pat. No. 5,128,726, U.S. Pat. No. 5,371,531, the disclosures of which are totally incorporated herein by reference, including especially acoustic ink processes as illustrated in the aforementioned copending applications and patents, such as an acoustic ink printer for printing images on a record medium.
The inks of the present invention in embodiments thereof are comprised of (1) a liquid non-aqueous vehicle with a boiling point higher than, or equal to about 150.degree. C. and lower than, or equal to about 350.degree. C., and more specifically from about 175 to about 325, and yet more specifically from about 225 to about 300 degrees Centigrade, and with a low acoustic loss to thereby reduce, or minimize energy consumption, and which low acoustic loss is for example, about below, or about equal to 60 dB/mm, (2) a solid alcohol additive compound with for example, a melting point of lower than, or about equal to 75.degree. C. and preferably between about 35 to about 74.degree. C. and an low acoustic loss to reduce, or minimize energy consumption, and which acoustic loss is for example, about equal to, or about below 100 dB/mm, (3) a water fastness quaternary compound, (4) a light fastness UV absorber, (5) a light fastness antioxidant, (6) and a colorant such as a dye, a pigment, mixtures thereof, mixtures of pigments, mixtures of dyes, and the like. More specifically, the present invention is directed to semi-solid hot melt acoustic ink compositions comprised of (1) non-aqueous alcohol liquid vehicles with a boiling point of for example, higher than, or equal to about 150.degree. C. and for example, lower than, or equal to about 350.degree. C., and preferably between about 170 and about 300.degree. C., and with a low acoustic loss of for example, below about, or equal to about 60 dB/mm, and preferably in the range of between about 5 to about 40 dB/mm, (2) a non-aqueous solid alcohol paper additive compound with a melting point of for example, lower than about, or equal to about 75.degree. C. and preferably between about 35 and about 74.degree. C., and with a low acoustic loss of for example, about below, or equal to about 100 dB/mm, and preferably in the range of between about 25 to about 80 dB/mm, (3) a waterfastness quaternary compound, (4) a UV absorber, (5) an antioxidant, and (6) a colorant, and wherein there can be generated with such inks excellent developed images on plain and coated papers with acceptable image permanence, excellent projection efficiency on transparencies without a post fusing step, and excellent crease resistance, and wherein the inks possess acceptable, and in embodiments superior lightfastness, and superior waterfastness. Moreover, in embodiments of the present invention there is enabled the elimination, or minimization of undesirable paper curl since water is not present, or minimal water is present. It is preferred that there be an absence of water, and when water is not present in the inks a dryer can be avoided thereby minimizing the cost of the acoustic ink jet apparatus and processes.